Regular Expressions 101

Pro

(?x)applies the following effective flags to the remainder of the pattern: gmx

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

^start of line

Group 1(-?([1-9]\d*[05])|-?5)

1st Alternative-?([1-9]\d*[05])

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 2([1-9]\d*[05])

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

\d*a digit, repeated any number of times

Character Class[05]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

2nd Alternative-?5

-?optionally matches the literal - (45₁₀ / 55₈ / 2D₁₆)

5the literal 5 (53₁₀ / 65₈ / 35₁₆)

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

(?x)
^(-?([1-9]\d*[05])|-?5)$